Mitsubishi Electric A1SX81-S2 Input Unit Module

The Mitsubishi Electric A1SX81-S2 is a 32-point digital input module for MELSEC-A series programmable logic controllers, delivering reliable signal acquisition from field devices in industrial automation. It accepts 24 VDC inputs with a typical current of ~7 mA per point, features photocoupler isolation, and uses terminal-block wiring to the base unit. Commonly installed in control panels, production lines, and machine automation systems, it processes discrete inputs from sensors, switches, and relays and serves to expand I/O or replace legacy modules. Weighing about 0.4 lb (0.18 kg), this module is compatible with MELSEC-A and AnS base units. It is a discontinued/legacy module. For migration or replacement, Mitsubishi offers common options including the standard A1SX81, the higher-capacity A1SX82, and the QX41 with an adapter for Q-series migration.